The present invention relates to a roll-on applicator of the type used to apply a liquid to a body surface. More particularly, the invention is directed to an improvement in an applicator ball-holding fitment, and improved means by which the applicator ball is positively sealed against a well-defined, firm, sealing ring when the cap is applied to the container as a closure therefor.
Ball-retaining fitments of the general type in which the present invention finds utility are well known in the art. For the most part, such prior art structures include sealing suraces against which the roll-on ball is stressed in order to seal the container against fluid loss or spillage during periods of non-use. Such prior art devices also include mechanical means by which the applicator ball is urged upwardly to clear the seat and to establish a fluid passage, when the closure or top is removed from the assembly. Additionally, such prior art structures also include mechanical means by which the ball is forcibly pushed downwardly to engage and bear against the sealing surface when the container is closed by application of the top.
In accordance with the present invention it has been discovered that there are important, critical relationships between the several mechanical elements which constitute the means by which the applicator ball is maintained in its various functional positions. It has been established, in accordance with the invention that only through adherence to precise, specific mechanical parameters and structural configurations can the operation of the fitment assembly be optimized. For example, prior art fitment structures have commonly utilized applicator ball sealing surfaces which are generally annular planar faces against which the ball abuts tangentially. In cooperation with such sealing faces, the prior art structures have also taught the use of substantially rigid and inflexible means by which the ball is pressed into engagement against the "planar" sealing surface. Such constant, positive pressure has the undesirable effect of inducing cold flow in both the applicator ball and the contacting sealing surface. As a result, surface irregularities develop in the ball and in the ball-contacting surface itself. These irregularities obviate effective subsequent sealing.
An additional structural deficiency of many of the prior art assemblies is that they fail to provide effective spring elements for elevating the ball to a position free of the sealing seat, with the result that the free-flow of liquid past the applicator ball is impaired. It is an important feature of the present invention that the above and other shortcomings and deficiencies of prior art applicator ball fitment constructions are obviated by providing an assembly in which each of the requisite functions is ensured through the use of a novel combination of intercooperating mechanical elements. These elements include spring tensioning support means for the applicator ball in combination with spring pressure elements for seating the ball, and a positive sealing wedge or ring against which the ball is resiliently secured.
A specific object of the invention is to provide a cap or closure with flexible pressure-applying fingers which exert an axial pressure against the applicator ball when the cap is in its top-closing position to force the ball downwardly and inwardly into the fitment to seat, in fluid sealing engagement, against the sealing ring of the fitment.
A related object of the invention is to provide such flexible pressure-applying fingers which will accommodate and compensate for any dimensional variability in tolerance between the fitment and the sealing ring so that the fluid-tight seal of the assembly will always be effective.
Another specific object of the invention is to provide a fitment which includes relief spring elements to bias the applicator ball upwardly and position the ball to clear the sealing ring so that an unpaired fluid passage is provided for application of the liquid to the surface to be treated.
A related feature of the invention is that with the cap removed from the assembly, spring-like elements engaging the undersurface of the applicator ball urge the ball upwardly to abut and to seal against a ball-encircling band at the mouth of the fitment to prevent spillage of fluid from the container. Inversion of the assembly and application of slight pressure against the ball serves to displace the ball from the sealing band and to permit fluid flow from the container.
Other and further objects, advantages, and features of the invention will be evident from the following description considered in conjunction with the drawings.